OUTLINES OP NATURAL PHILOSOPHY. 



Though it is proved to demonstration, from facts 

 above enumerated, that the Earth is far from being 

 the centre of the planetary motions, yet all the ap- 

 pearances hitherto mentioned, are consistent with 

 what is calledjthe TYCHONIC System of the heavens, 

 (from its inventor TYCHO BRAKE'), in which the 

 Sun, accompanied by the planets, revolves in an or- 

 bit round the Earth. This system, which its want 

 of simplicity renders suspected, is entirely over- 

 turned by the fact of the aberration, and the mo- 

 tion of the Earth completely established. 



When the aberration was first discovered, it was 

 thought that the velocity of light, as inferred from 

 the eclipses of the satellites of Jupiter, did not per- 

 fectly agree with it. It has, however, been found, 

 from more accurate comparisons, that they per- 

 fectly coincide. 



215. It appears, that the light of the heaven- 

 ly bodies- traverses the spaces between them 

 and the earth with the same uniform velocity. 



The reflected light from the satellites, travels with 

 the same velocity with the direct light of the fixed 

 stars ; and the velocity of this last is the same from 

 whatever distance it comes. 



There is reason to think, that light is accelerated 

 by the action of transparent bodies. If so, these 

 bodies also impart to light a velocity in the direc- 

 tion of the earth's motion, and proportional to the 



increase 



